Nice looking tank there. I managed to cycle my spec v pretty quick using media from my other tank. That took just over two weeks I think. So I suppose it is possible for yours to be about right. Maybe monitor it a little while longer just to make sure it stays the same.
Good choice with the dwarf puffers. I'm waiting to get my first pair at the weekend. I'm so excited for them. It's amazing how curious they are and so full of character